A specialized breed of an­cient gray wolves once roamed Alas­ka’s icy ex­panses, with bone-crushing jaws for tak­ing on huge prey, scientists say.

The ex­tinct Alas­kan wolves had ro­bust bod­ies, strong jaws, and mas­sive ca­nine teeth for kill­ing prey larg­er than them­selves and reg­u­larly con­sum­ing large bones, ac­cord­ing to the re­search­ers. But the wolves ap­par­ently died out along with oth­er big an­i­mals at the end of the last Ice Age.

“The un­ique at­tributes of Alas­kan Pleis­to­cene [Ice-Age] wolves had not been pre­vi­ously rec­og­nized,” said Blaire Van Valken­burgh of the Un­ivers­ity of Cal­i­for­nia, Los An­ge­les, one of the re­search­ers. “The liv­ing gray wolf dif­fers dra­mat­ic­ally from that which roamed Alas­ka just 12,000 years ago.” The find­ings ap­pear in the June 21 on­line is­sue of the re­search jour­nal Cur­rent Bi­ol­o­gy. 

The gray wolf is one of the few large preda­tors that sur­vived the mass ex­tinction of the late Ice Age. Nev­er­the­less, wolves disap­peared from north­ern North Amer­i­ca at that time, she said; but they lived on in the Old World, which may ex­plain their pre­sence in North Ame­rica to­day.

To study Alas­ka’s an­cient wolves, Van Valken­burgh and col­leagues col­lect­ed bones of the an­i­mals from per­ma­frost de­posits and ex­am­ined their chem­i­cal com­po­si­tion and DNA. The late-Pleis­to­cene wolves were ge­net­ic­ally and phys­ically dis­tinct from ex­ist­ing wolves, the sci­en­tists re­ported: the skull shape, tooth we­ar and bone chem­istry sug­gest they were hunters and scav­engers of ex­tinct mega­fauna.

The archaic wolves had “more mas­sive teeth and broader skulls with shorter snouts, en­hanc­ing their abil­ity to pro­duce strong bites,” Van Valken­burgh said. “The stud­ies of their tooth wear and frac­ture rate showed high lev­els of both, con­sist­ent with reg­u­lar and fre­quent bone-cracking and -crunching.”

Those char­ac­ter­is­tics probably came in handy in an­cient Alas­ka, where the wolves faced stiff com­pe­ti­tion for food from some for­mi­da­ble com­peti­tors, she added, in­clud­ing li­ons, short-faced bears, and saber-tooth cats. Dur­ing pe­ri­ods of in­tense com­pe­ti­tion among preda­tors, mod­ern wolves al­so con­sume car­casses more ful­ly, she noted. They in­gest more bone and eat faster, in­creas­ing the risk of tooth frac­ture.

The long-ago de­mise of this spe­cial­ized wolf form may por­tend things to come for spe­cial­ized groups of ex­ist­ing preda­tors, Van Valken­burgh said. For ex­am­ple, a un­ique type of no­mad­ic North Amer­i­can gray wolf was re­cently dis­cov­ered. Packs of them mi­grate across the tun­dra along with car­i­bou and keep their num­bers in check. In con­trast, oth­er wolves are ter­ri­to­rial and non-migratory. “Global warm­ing threat­ens to elim­i­nate the tun­dra and it is likely that this will mean the ex­tinction of this im­por­tant preda­tor,” she said.

Courtesy Cell Press and World Science staff